Question

Give reason 

(a) C and Si are always tetravalent but Ge, Sn, and Pb show divalency. 

(b) Gallium has higher ionization enthalpy than Al.Explain.

Answer 1

(a) Ge, Sn and Pb show divalency due to inert pair effect, Pb²⁺is more stable than Pb⁴⁺. 

(b) Due to poor shielding effect of d-electrons in Ga, effective nuclear charge increases as compared to Al. Thus the I.E of Ga is higher than Al.